When I log into the server by putty (ssh) and typing that exactly command, it works fine.

Also tried to remove the sh from the line so that the code is:
/var/www/scripts.ph-tvs.nl/web/sat/getimage.sh
it is not working.

I know that cronjobs are working in ISPConfig because I have another cronbjob in ISPConfig that is working fine. But that is an url cronjob.http://www.mywebsite/cron.php <- working fine.
Client has full cron in the client options menu.

Can someone please explain to me why it isnt working in ISPConfig and why it is working fine by ssh?